The field of the present invention relates to portable containers for transporting an electrically sensitive device, and carrier devices for storing and shipping such containers. More particularly, the field of the present invention includes containers which, while closed, protectively shield their contents from potentially harmful external electrical forces, and carrier devices capable of transporting one or more of such containers in an efficient manner.
Circuit boards are typically stored and carried in carriers having the capacity to store several such circuit boards at one time. These circuit boards are often either unprotected, or else are kept in antistatic bags. These antistatic bags are sometimes nickel-coated. An undesirable triboelectric effect can result from sliding these ungrounded bare or bagged circuit boards from the multicard carrier.
These carriers are often ribbed to provide slots for the insertion of each circuit board to be stored. In injection molding processes, ribs as narrow as 1/16 inch can be produced. However, in blow molding technology, typically the minimum width of each rib of the carrier must be 1/4 inch to 3/8 inch in thickness.
While it would be more desirable to utilize narrower ribs to permit more circuit boards and the like to be stored within a given sized carrier, molds for injection molding processes are considerably more expensive and complex than molds utilized for blow molding processes since injection molds are made of heat treated steel to very close tolerances, and polished to a high degree of finish.
It would, therefore, be desirable to provide a carrier which can be produced by a blow molding process, and yet permit much tighter packing of circuit boards and similar devices than is presently available in the blow molded art.
It would also be beneficial to provide protection of such circuit boards from triboelectric and other electrical damage resulting from storage of bare or inadequately protected circuit boards in a carrier device.
It is, therefore, an object of the present invention to provide a blow molded carrier for circuit boards and the like which permits more efficient placement of the circuit boards within the carrier device.
Containers have been developed, especially containers for portable use, as for example, in the device replacement market, which protect electrically sensitive devices from damage. One type is a small box like container that houses conductive, sponge or foam sheets into which the device terminals are temporarily embedded. An example is found in U.S. Pat. No. 4,333,565. A portable work station is described in U.S. Pat. No. 4,494,651 in which electrically conductive material, such as carbon black particles, is blended with thermoplastic material to make an electrically conductive case.
It would be highly desirable to make use of such electrically conductive cases, in connection wih blow molded carriers for transporting several such cases in an efficient manner.